Can anyone tell me the symptoms of an internal layer? I have a Black Copper Marans hen who is 39-40 weeks old and STILL has not laid an egg! She gets in a nest box every day, acts like she's laying an egg and even sings the "egg song"--- but no egg. I have watched the whole process, so I know she's not an egg eater. She spent one whole day and night in a nest box and I almost thought she was broody-- but now she's back to the old routine. This hen is big and beautiful and glossy-- just can't seem to produce an egg. Any advice??